The Identification of War-fighting Symbology With the Use of a Small Display

Report No. ARL-TR-3807
Authors: Kimberly Myles
Date/Pages: May 2006; 30 pages
Abstract: Two studies were conducted to evaluate the effects of symbol size and screen clutter on symbol identification when one is using a small map display. The purpose of the first study was to determine the minimum threshold symbol size for a group of selected war-fighting symbols that could be discriminated and identified on a 3.5-inch simulated wrist map display. The Best PEST (Parameter Estimation by Sequential Testing) psychophysical adaptive procedure was used to obtain symbol size thresholds for a no-map and map environment with 20 active-duty Soldiers. A True Type font of 16 points was found as the minimum symbol size at which 95% of the responses were predicted to be accurate. The second study aimed to determine the number of symbols (defined as clutter) that could be displayed on the 3.5-inch display, when one is using a rural and urban map display, without significant decreases in performance. Eight active-duty Soldiers determined if target symbols were present on or absent from map images containing distractor symbols. Performance was measured via scan time and response accuracy. For the urban map display only, mean scan times began to increase at the clutter level of nine symbols and continued to increase at a clutter level of 12 symbols. A response accuracy of 92% was obtained with incorrect responses falling randomly across treatments. These results show that a symbol size of 16 points is adequate for symbol identification when the symbol is embedded on a 3.5-inch map display. Also, if the map background does not perceptibly contribute to display clutter, superimposing as few as three or as many as 12 symbols over the map will yield no change in scan time for a target symbol. Based on these findings, it is reasonable that the symbol information that Soldiers retrieve from this display will be legible and organized, which will help to increase the Soldier?s situational understanding of his environment and decrease the amount of time the Soldier devotes to gathering information for critical decision making.
Distribution: Approved for public release
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Last Update / Reviewed: May 1, 2006